Polonium

Frae Wikipedia
Jump to navigation Jump to search
Polonium,  84Po
File:Polonium.jpg
General properties
Appearance sillery
Mass nummer 209 (most stable isotope)
Polonium in the periodic cairt
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium
Te

Po

Lv
bismuthpoloniumastatine
Atomic nummer (Z) 84
Group group 16 (chalcogens)
Period period 6
Element category   poor metal
Block p-block
Electron confeeguration [Xe] 6s2 4f14 5d10 6p4
Electrons per shell
2, 8, 18, 32, 18, 6
Pheesical properties
Phase (at STP) solit
Meltin pynt 527 K ​(254 °C, ​489 °F)
Bylin pynt 1235 K ​(962 °C, ​1764 °F)
Density (near r.t.) (alpha) 9.196 g/cm3
(beta) 9.398 g/cm3
Heat o fusion ca. 13 kJ/mol
Heat o vapourisation 102.91 kJ/mol
Molar heat capacity 26.4 J/(mol·K)
Vapour pressur
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K)       (846) 1003 1236
Atomic properties
Oxidation states 6, 5,[1] 4, 2, −2
(amphoteric oxide)
Electronegativity Pauling scale: 2.0
Atomic radius empirical: 168 pm
Covalent radius 140±4 pm
Van der Waals radius 197 pm
Color lines in a spectral range
Miscellanea
Creestal structurcubic
Cubic creestal structur for polonium
Thermal expansion 23.5 µm/(m·K) (at 25 °C)
Thermal conductivity ? 20 W/(m·K)
Electrical resistivity (α) 0.40 µ Ω·m (at 0 °C)
Magnetic orderin nonmagnetic
CAS Nummer 7440-08-6
History
Diskivery Pierre Curie an Marie Curie (1898)
First isolation Willy Marckwald (1902)
Main isotopes o polonium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
208Po syn 2.898 y α 204Pb
β+ 208Bi
209Po syn 103 y α 205Pb
β+ 209Bi
210Po trace 138.376 d α 206Pb
| references | in Wikidata

Polonium is a chemical element wi the seembol Po an atomic nummer 84, discovered in 1898 bi Marie Curie an Pierre Curie. A rare an heichly radioactive element wi na stable isotopes, polonium is chemically seemilar tae bismuth an tellurium, an it occurs in uranium ores. Applications o polonium are few, an include heaters in space probes, antistatic devices, an soorces o neutrons an alpha particles. Acause o its poseetion in the periodic cairt, polonium is whiles clessifee'd as a metalloid.[2] Ither soorces say that on the basis o its properties an behaviour, it is "unambiguously a metal".[3]

References[eedit | eedit soorce]

  1. Thayer, John S. (2010). Chemistry of heavier main group elements. p. 78. doi:10.1007/9781402099755_2. 
  2. "Characterizing the Elements". Los Alamos National Laboratory. Retrieved 4 Mairch 2013. 
  3. Hawkes, Stephen J. (2010). "Polonium and Astatine Are Not Semimetals". Journal of Chemical Education. 87 (8): 783. Bibcode:2010JChEd..87..783H. doi:10.1021/ed100308w.